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Groups > comp.lang.python > #94540

scalar vs array and program control

From Seb <spluque@gmail.com>
Subject scalar vs array and program control
Date 2015-07-24 23:18 -0500
Organization Church of Emacs
Newsgroups comp.lang.python
Message-ID <mailman.971.1437797935.3674.python-list@python.org> (permalink)

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Hello,

I'm fairly new to Python, struggling to write in a more object-oriented,
functional style.  I just wrote a function that takes two arrays
representing sine (y) and cosine (x) angle coordinates, and returns the
angle in degrees.  I had initially written the function to take
array-like arguments x/y, but I'd like to generalize and take scalars as
well.  However, the function has a subsetting operations, which don't
work with scalars:

    vmag = np.sqrt((x ** 2) + (y ** 2))
    ang = np.arctan2(y, x)
    ang[ang < 0] = ang[ang < 0] + (2 * np.pi) # output range 0 - 2*pi
    ang[vmag == 0] = 0          # when magnitude is 0 the angle is also 0
    ang[ang == 0] = 2 * np.pi   # convention

If I want to take scalars x/y, I naively thought about implementing an
if/else statement right before the subsetting operations.  However, my
intuition tells me there must be a proper object-oriented solution to
this.  Any tips appreciated.

Cheers,

-- 
Seb

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scalar vs array and program control Seb <spluque@gmail.com> - 2015-07-24 23:18 -0500
  Re: scalar vs array and program control Steven D'Aprano <steve@pearwood.info> - 2015-07-26 14:03 +1000

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